I'm not sure if this is a new problem or if it is a problem at all. When I shut my iMac down and restart, the screen is entirely white with no options showing. If I restart and hold the 'option' button down, I will be presented with the HDD icon and an arrow. Pressing the arrow allows the unit to start up to my desktop. Is this a normal operation?

You should only hold down the option key during start-up if you want to boot in to your windows partition, if you have one. Otherwise don't press anything and during the start-up an apple should show on the screen and then boot in to OSX.

Thanks - I did as suggested - the HDD was the first item in the startup, but I highlighted it anyway. I restarted, waited quite a while and it started with the OS-x system. Thanks for the advice. It is now workign as I had hoped.

To repair disk permissions you need to open Disk Utility (search for it in Spotlight if you're not sure where it is), choose your hard drive in the list, and click the Repair Disk Permissions button. It will take a while to complete and you might see a bunch of lines of text - this is all normal. When it's done you can restart your computer and see if it fixed your problem.

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